1. Field of the Invention
The present disclosure relates to integrated circuits, and more particularly to wire bonds for integrated circuits, MEMS devices, and the like.
2. Description of Related Art
Wires in power electronics are used to conduct current to and from a device package. The package wires are attached to the electronic components inside the package by way of wire bonds. During operation power electronic modules are subject to temperature sway. Particularly at the wire bonds for semiconductor chips, significant temperature variation can be observed. Wire material, i.e., aluminum and copper, and semiconductor chips, i.e. silicon, have different thermal expansion coefficients. Under the elevated temperature, the wire bond is subject to shear load due to the thermal expansion mismatch. This can lead to wire bond failure. The intensity of thermal mismatch is directly related to three key factors: the temperature sway amplitude, the bond dimension, and the difference in the coefficients of thermal expansion (CTE). Each of these key factors can compromise the reliability of the wire bond. Most work focus on the reduction of the thermal temperature sway by meanings as improvement of the bonding technology to reduce the contact electrical resistance, or use large bond to reduce the current density.
Various approaches have been developed to improve wire bond reliability. The mostly widely used concept is known as double stitch bonding. Instead of one stitch per wire, each wire is stitched multiple times onto a semiconductor chip. Another approach is using a flat ribbon wire instead of a round ribbon wire. The flat ribbon wire can achieve a relatively narrow bond with a bigger contact area. However, the bond dimension of either of these approaches is not reduced.
Such conventional methods and systems have generally been considered satisfactory for their intended purpose. However, there is still a need in the art for improved wire bonds. The present disclosure provides a solution for this need by using a plurality of wire bonds with smaller dimensions.